This invention relates to a process for separating one ar,ar-dihalo-ar-alkylbenzene from a mixture of ar,ar-dihalo-ar-alkylbenzenes.
Processes for the preparation of isomeric mixtures of ar,ar-dihalo-ar-alkylbenzenes are known in the art. For example, U.S. Pat. No. 2,186,960 to Dreisbach et al. discloses the preparation of polyisopropylhalobenzenes by reacting a halobenzene containing not more than four halo groups per benzene ring with an alkylating agent in the presence of a Friedel-Crafts catalyst such as aluminum trichloride.
Unfortunately, as taught in column 2, lines 19-26 of U.S. Pat. No. 2,186,960, the polyisopropyl halobenzenes are extremely difficult if not impossible to separate. Subsequent to the issuance of the aforementioned patent, it has been discovered that certain isomers of isopropyl halobenzenes are useful precursors in the manufacture of compounds exhibiting excellent biological activity.
In view of the severe difficulties existent in the conventional processes for preparing and separating such compounds from isomeric mixtures thereof, it would be highly desirable to provide an improved process for separating ar,ar-dihalo-ar-alkylbenzenes.